1. Technical Field
Example embodiments of the present invention relate in general to a method for device-to-device communication, and more specifically, to a method for implement device-to-device communication in a cellular communication network.
2. Related Art
Device-to-device communication (hereinafter, also referred to as D2D communication) is a communication method that performs direct data transmission and reception between two adjacent terminals, not via a base station. That is, two terminals become a source and a destination of data, respectively.
There are several discussions about use cases for efficiently utilizing this device-to-device communication. As an example, device-to-device communication may be applied to a local media server for providing a large amount of data (for example, programs of rock concerts, information about musicians, etc.) for audiences who attend rock concerts.
In this case, each device accesses a serving cell to perform phone calls and Internet access with an existing cellular link while the device may directly transmit and receive the large amount of data to and from a local media server that operates as in D2D communication with the device.
D2D link may be enabled not only between devices having the same serving cell, but also between devices having different serving cells. For example, a third device in a first base station may perform D2D communication with a sixth device in a second base station.
This device-to-device communication includes a centralized control D2D communication method and a distributed control D2D communication method.
In the centralized control D2D communication method, a device that intends to communicate with other devices may request a central node that performs control (for example, a base station in a cellular communication network) to establish a link, and the central node may allocate wireless resources for device-to-device communication between two devices to allow communication between the devices when the devices are adjacent to each other. In this case, the central node may mange almost all operations of the devices, and the wireless resources allocated for a cellular link in D2D communication or another D2D link may be reused.
In the distributed control D2D communication method, a device may establish a link in a distributed control way (that is, by direct signal exchange between devices), independently of one central control node, to directly exchange data with neighboring devices. This distributed control device-to-device communication includes FlashLinQ from Qualcomm as a standard. FlashLinQ is a synchronous TDD (Time Division Duplexing) technology.
The above D2D communication method may have several advantages and disadvantages, compared to an existing cellular communication system. Accordingly, a communication system where the above D2D communication method is combined with the cellular mobile communication system, is expected to be widely used. However, the distributed control D2D communication method is not considered in the current cellular communication network, and also the current cellular communication network does not provide a solution for performing both existing cellular communication and D2D communication.